Online Banking

Why is it that in this day and age it takes a day to transfer money from one bank to another? And if it’s a weekend or public holiday it takes even longer. Do computers not work weekends now?

Can someone please invent a protocol or process to allow bank transfers to be instant? Surely it can’t be that hard, it’s just numbers/data being shifted around. I can transfer entire DVDs of information from one side of the world to the other in a short period of time, why can’t a bank process things in real time?

When internet banking started it was pretty instant, then I think it was dialled back because of fraud (much more difficult if there’s a 3 day gap between transfer and credit). Not sure of this: would be nice to hear from someone in banking.